Increased urinary methylmalonic acid excretion in breast-fed infants of vegetarian mothers and identification of an acceptable dietary source of vitamin B-12

Am J Clin Nutr. 1988 Jan;47(1):89-92. doi: 10.1093/ajcn/47.1.89.


Increased urinary methylmalonic acid (UMMA) concentrations might indicate vitamin B-12 deficiency. Our study tested the hypothesis that elevated UMMA in breast-fed infants is associated with decreased maternal serum B-12 concentrations. UMMA concentrations were measured in 17 vegetarian mothers and their infants and in six infants of nonvegetarian mothers. Serum vitamin B-12 concentrations were determined in all mothers. Range of UMMA for vegetarian infants (3-924 mcg/mg [2.6-790.9 mumol/mmol] creatinine) was much broader than that for omnivorous infants (2-25 mcg/mg [1.7-21.4 mumol/mmol] creatinine). Maternal UMMA and serum vitamin B-12 were negatively correlated (r = -0.700, p = 0.003). Infant UMMA concentrations correlated positively with maternal UMMA concentrations (r = 0.686, p = 0.003) and inversely with maternal serum vitamin B-12 concentrations (r = -0.681, p less than 0.001). In three infants with high UMMA concentrations, vitamin B-12 treatment (oral B-12, vitamin B-12 injection, or a modification of maternal diet within the vegetarian philosophy) led to an abrupt decrease of UMMA.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Breast Feeding*
  • Creatinine / urine
  • Diet, Vegetarian*
  • Female
  • Food Analysis
  • Humans
  • Infant
  • Malonates / urine*
  • Methylmalonic Acid / urine*
  • Vitamin B 12 / administration & dosage*
  • Vitamin B 12 / analysis


  • Malonates
  • Methylmalonic Acid
  • Creatinine
  • Vitamin B 12